Blood test has conventionally been employed as an important tool to monitor health condition, postoperative course, and medication effects in the subjects. For example, glucose level management is an essential for hyperglycemic patients. Then, when an insulin infusion is performed, the glucose level management after each meal has also to be performed under supervision of physician in addition to the conventional glucose level management prior to each meal and bed time.
Recent years, the glucose level management can be performed without significantly changing the daily life by performing self glucose determination at home or office. About 200 μm of scratch is made at fingertip with small puncture device called as Lancet and several μL of blood are collected. Then, glucose level is determined by applying the blood so collected onto small sensor. This is a typical glucose determination method.
However, excruciating pain was generated at the collecting of the blood, and it was unacceptable physical pain and emotional distress for the subjects. Accordingly, a method for collecting blood with less physical damage has been desired.
As one means to solve this problem, there is a device which allows smooth collection of blood by forming minimum incision portion and opening it with pressure or tension applied around the incision portion.
According to such device, a needle with blade surface at the tip thereof is punctured into the skin. FIG. 17 shows a general puncture needle. The general needle has three polished surfaces at its tip. FIGS. 18 (a)-(c) illustrate how an incision portion is formed by puncturing the needle into the skin. FIG. 18 (a) illustrates how a tip of the needle is slightly punctured into the skin. Then, FIG. 18 (b) illustrates how the incision portion is expanded by deeply puncturing into the skin tip of the needle. Finally, FIG. 18 (c) illustrates how the skin at both sides of the incision portion is approached by removing the needle from skin.
There is a conventional skin incision instrument to form the incision portion as illustrated in FIG. 18 (c).
For example, according to Patent Publication 1, a blood collection device with needle is positioned onto the skin and it is pressed downwardly thereat. The blood collection device comprises a skin expander unit, and then uniform puncture for the skin can be realized by expanding the skin in the target area under the blood collection device with the skin expander unit. As a result thereof, the blood can be collected with less physical damage.
Patent Publication 2 discloses a vessel surgery device for professional use. The vessel surgery device comprises the vessel support which holds a part of the vessel and the incision device which incises the vessel. The vessel support comprises a pair of arms and needles mounted respectively around the tip of the arm, and it can support the vessel by puncturing the needles into the vessels. Further, by rotating the turn buckle mounted between the both arms, the arms would be opened and be shut, thereby, the space between both needles is adjusted and such state can be maintained. Then, by pressing a manual operation button of the incision device, blade was inserted between both needles, and the blood vessels can be incised thereby.
Patent Publication 3 discloses a skin incision instrument which can easily collect blood by incising a part of skin with a needle, pressing downwardly a skin stimulator after the needle is removed from the incision portion, and forming the incision portion.
Particulars of the skin incision instrument disclosed in Patent Publication 3 are as follows. FIG. 19 and FIG. 20 illustrate an overall view and an enlarged view of the skin incision instrument, respectively. Identical symbols are denoted for the identical elements between FIG. 19 and FIG. 20. As illustrated in FIG. 19 and FIG. 20, first of all, the incision instrument 10 is pressed to the skin 13. Inside of the incision instrument 10 comprises the lever 18, and the skin 13 is pressed downwardly by pushing down the lever 18 inwardly. Thereby, the blood is collected by expanding the skin 13 and forming the incision portion 19. In addition, the collection of blood is promoted by heating or vibrating the lever 18.